1. Field of the Invention
This invention relates to electronic circuits for automatically zeroing or nulling an analog offset voltage.
2. Description of the Prior Art
In the course of measuring and displaying physical or electrical quantities a variety of electromechanical and electronic devices are commonly used. For example, a method of measuring a physical dimension of a machined part is to use an electromechanical transducer which comes into physical contact with the machined part. The transducer generates an electrical signal corresponding to the physical dimension, and this signal is electronically processed and displayed. However, analog offset voltages are introduced into the system by the normal operation of the electromechanical and electronic devices within the system. These devices include, for example, the electromechanical transducer and operational amplifiers. Therefore, in order to display a correct measurement, it is necessary to manually zero the system to compensate for the analog offset voltage. In addition there are situations where an analog offset voltage is intentionally inserted at the input of a signal processing system, but where it is no longer desirable to retain the offset voltage at the output of the signal processing system. Accordingly, it is desirable to provide an electronic method for automatically zeroing the analog offset voltage.